c# 将新对象添加到对象上下文返回“更新条目时发生错误”，主键重复条目

发布于 2024-07-30 01:11:35 字数 1602 浏览 5 评论 0原文

我在尝试将对象添加到实体框架中的对象上下文时遇到问题。

代码如下：

//related object ids are retrieved from another context.
//since I thought the problem could be linked to object loaded in this context, I tried to
//close it and start on a fresh object context... 
int idetab = currentEtab.Id;
long idnivcycle = selectedNivcycle.id_nivcycle;
long idanscol = AnneeScolaireEnCours.id_annee_scolaire;
//and this context is closed
context.Dispose();


//This is the new object context
objectcontextEntities ctest = new objectcontextEntities();
//from where I retrieve all the objects I want to link to the object I want to create :            
Nivcycle niv = ctest.Nivcycles.Where("it.id_nivcycle=@id", new ObjectParameter("id", idnivcycle)).First();
Etablissement eta = ctest.Etablissements.Where("it.Id=@id", new ObjectParameter("id", Convert.ToInt32(idetab))).First();
annee_scolaire an = ctest.annee_scolaire.Where("it.en_cours = @id", new ObjectParameter("id", Convert.ToSByte(true))).First();
// Now I try to create my new object           
Composante co = new Composante();
co.Nom = "test";
co.Nivcycle = niv;
co.Etablissement = eta;
co.AnneeScolDeb = an;
ctest.AddToComposantes(co);
ctest.SaveChanges();
ctest.Dispose();

在 SaveChanges() 上，我收到一个 UpdateException，表示键“PRIMARY”有重复条目“0”。确实，我的“Composantes”中已经有一个 id=0 的对象。如果我删除它，我至少可以创建一个ID=0的对象。我不明白的是，当一个新对象添加到上下文中时，为什么它不采用下一个可用的 ID？？？这与我尝试在新上下文中创建此对象之前发生的错误完全相同......这可能是因为我的 model.edmx 中缺少参数？有没有办法强制将新 id 归因于新创建的对象？

我使用实体框架模型连接到 mysql 数据库，使用 Devart dot.connector 连接到数据库。预先感谢大家对这个简单问题的答复。

皮埃尔

原文

I'm having a problem trying to add an object to an object context in Entity Framework.

Here is the code :

//related object ids are retrieved from another context.
//since I thought the problem could be linked to object loaded in this context, I tried to
//close it and start on a fresh object context... 
int idetab = currentEtab.Id;
long idnivcycle = selectedNivcycle.id_nivcycle;
long idanscol = AnneeScolaireEnCours.id_annee_scolaire;
//and this context is closed
context.Dispose();


//This is the new object context
objectcontextEntities ctest = new objectcontextEntities();
//from where I retrieve all the objects I want to link to the object I want to create :            
Nivcycle niv = ctest.Nivcycles.Where("it.id_nivcycle=@id", new ObjectParameter("id", idnivcycle)).First();
Etablissement eta = ctest.Etablissements.Where("it.Id=@id", new ObjectParameter("id", Convert.ToInt32(idetab))).First();
annee_scolaire an = ctest.annee_scolaire.Where("it.en_cours = @id", new ObjectParameter("id", Convert.ToSByte(true))).First();
// Now I try to create my new object           
Composante co = new Composante();
co.Nom = "test";
co.Nivcycle = niv;
co.Etablissement = eta;
co.AnneeScolDeb = an;
ctest.AddToComposantes(co);
ctest.SaveChanges();
ctest.Dispose();

On SaveChanges(), I receive an UpdateException, saying that there is a duplicate entry '0' for Key 'PRIMARY'.
It is true that I already have an object in my "Composantes" with id=0. And if I delete it, I can at least create one object with ID=0. What I don't understand is that when a new object is added to the context, why doesn't it take the next available ID ???? This is exactly the same error that was happening before I tried to create this object in a new context.... This is maybe because of a missing paramter in my model.edmx ? Is there a way somewhere to force the attribution of a new id to the newly created object ?

I'm connecting to the mysql database using an entity Framework Model using Devart dot.connector to connect to the database.
Thanking all of you in advance for your reply to this simple question.

Pierre

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